A dipole antenna element has been disclosed, for example, in WO 00/39894, or likewise in U.S. Pat. No. 6,313,809 B1. This is a dual-polarized antenna element arrangement having two or more dipoles which, in a plan view, are each arranged in the form of a dipole square, or at least similar to a dipole square. The antenna element arrangement which is in the form of a dipole square or the antenna element arrangement which is at least approximately a dipole square (in a plan view as seen from its exterior) is connected and fed such that, from the electrical point of view, the antenna element arrangement transmits and receives in two mutually perpendicular polarization planes, which run parallel to the mutually perpendicular diagonals which are formed by the antenna element arrangement.
A dual-polarized antenna element arrangement such as this has been proven well in practice and has major advantages over previous antenna element arrangements.
The exemplary illustrative non-limiting technology herein provides a further improved antenna element arrangement which has even better characteristics particularly in terms of a broad bandwidth.
It must be regarded as more than surprising that it has been possible to considerably further improve the broad bandwidth of an antenna element arrangement of this generic type, by means of simple technical measures. Specifically, according to exemplary illustrative non-limiting arrangements, this can be achieved by each of the four dipole halves that are produced from the electrical point of view (from the antenna element arrangement which transmits and receives in the manner of a dipole cruciform from the electrical point of view) each has an electrically conductive transverse strut, which runs transversely and preferably at right angles to the electrical polarization plane. The antenna element arrangement which forms this generic type is thus distinguished in that each dipole half is formed by two mutually perpendicular, or at least approximately mutually perpendicular, half-dipole components. The half-dipole components may be conductively connected at their end. However, they may also be only mechanically fixed with respect to one another and may have an electrically conductive connection in a strut or in the form of a strut, which is located offset with respect to their end as mentioned above (and at which they may be, but need not be, fixed with respect to one another, as mentioned).
It has now been found that the measures explained above allow the broad bandwidth of an antenna to be considerably further improved.
In one exemplary non-limiting illustrative implementation, this cross connection is in this case in the form of a transverse strut.
The extensions of the half-dipole components, which run at an angle and preferably at right angles to one another, may be as mentioned conductively or mechanically fixed to one another at their intersection point, which is also referred to in the following text as their outer corner point. Those ends of the two half-dipole components which are in each case on the inside with respect to this and which form the respective half-dipole are preferably used as connecting points, which are connected to one another by an electrical cable or an electrically conductive structure. In principle, the electrical cross connection may, however, also be arranged or electrically linked at some other point between the two respectively interacting half-dipole components. The electrical cross connection or transverse strut is preferably in the form of a straight transverse strut, which is located at right angles to the corresponding polarization plane. However, in a plan view, it may also be at least slightly convex or concave, or may be formed with other curved sections. It may likewise also be at least partially run other than in the plane in which the individual half-dipole components are located. In other words, the transverse strut may also run at a distance from this plane, somewhat above or below it, with the plane which has been mentioned above generally being that plane in which all the half-dipole components are arranged. This plane is normally parallel to the reflector plane.
The respectively interacting half-dipole components may be electrically firmly connected in the outer corner regions, or else may be only mechanically connected there via a nonconductive electrical connecting piece. The corner regions may likewise be open.
The cross connection or transverse strut that has been explained may, however, likewise be in the form of a flat element. In this exemplary case, an opening area preferably remains in the outer corner region, passes through the flat arrangement of the dipole half formed in this way, and is preferably larger than at least 20% of the total area of a respective dipole half. This opening area, which passes through the dipole surface, opens in a separation space between the outer half-dipole components, which run towards one another, can also be interpreted as edge boundaries of the respective dipole half. In this exemplary non-limiting illustrative implementation, the outer half-dipole components are not electrically connected to one another in their outer corner region.
In this exemplary non-limiting illustrative implementation, the dipole halves are formed from flat elements, with the boundary edges (which point towards one another) of two adjacent dipole halves which are associated with a different polarization being arranged symmetrically, and in this case preferably running parallel to one another. In a plan view, the flat dipole halves in this case each have a square shape or a shape similar to a square, with the respective outer boundaries which are located on the outside and run towards one another in their outer corner regions ending at least at a short distance from one another and having a connection through the separation area formed in this way to an opening or aperture area which passes through the flat dipole half. This opening area should have at least 20% of the area of the dipole halves. Otherwise, the flat dipole halves may also have further openings, for example even being in the form of grids or meshes. The flat elements of the dipole halves thus carry out that function which, in the exemplary non-limiting illustrative implementation, is carried out by the electrical cross connections or transverse struts mentioned there.
The dual-polarized antenna having flat antenna elements has in principle also been disclosed in U.S. Pat. No. 6,028,563. The dipole arms or dipole halves in this case are triangular, however, that is to say the dipole halves do not themselves have a square structure. Furthermore, that flat dipole halves which are known from the abovementioned prior art are not provided with apertures.